Starting with the corners, and using vid's guide to cabinet restoration.
https://pinside.com/pinball/forum/topic/cabinet-restoration-vids-guide
I started by scoring the damaged corner with a razor, and adding a short wood screw raised a little bit for "tooth". (according to vid)
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Here is the resin I used, made by bondo.
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I didn't have any aluminum laying around so I used a cut up manilla folder and some wax paper. (I guess it's better than tape) I can definitely see where having a nice thin piece of waxed aluminum would be helpful.
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Resin applied
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After letting it cure overnight (it only needs a few hours really) and sanding down flat here is what I was left with. I'm very happy with the result.
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Here is a corner that turned out really nice.
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A few lessons I learned.
You need a lot less resin than you think.
A little hardner goes a long way.
Wear gloves (nitrile, latex, etc.) once it gets on your hands its terrible to get off.
I found that applying it with the tongue depresser was a lot more controlled and less messy than pouring directly out of the cup.
Wear a dust mask when sanding